Selecting Windows & Doors for Home Renovation

Windows & Doors / Comments and Recommendations

The selection of windows and doors for your project, as well as the various materials that are being used in their production, is an important decision for the homeowner. Whether the selection of windows and doors is being made for use as primary windows and doors within a new home, or are required as replacement windows or doors for an existing home, there are several basic characteristics and observations, that should be carefully considered.

The actual design and engineering of the windows and doors will make a difference in the appearance , the functionality, as well as the future maintenance requirements of these windows and doors. In most cases there are several basic parts of windows and doors that are common to all of these products. At the end of this webpage is a listing of common terms and descriptions to assist you in understanding your window and door package. As with everything else in your home, a basic understanding of the product will better qualify you to make the proper decision.

First it would be beneficial to understand the types of windows and doors available. This is not meant to identify all there is in window and door availability, however, it will provide a foundation for an understanding of the products, and a sense of how to communicate, as you select your doors and windows.

                  Types of common windows;

  • Double hung window. This type of window is probably the most common window for residential construction. The double hung window is just what the name indicates. The window itself consists of two window pieces, which are called window sashes. These sashes slide on window tracks that are mounted to the interior sides of the window frame. The double hung window can be obtained in equal size sashes or sashes that are different in sizes, dependent on the architectural design of the window. A window that has different size sashes is commonly referred to as a cottage window. In a standard double hung window, both the upper and the lower sashes can slide past one another to allow any variation of top and bottom opening and closing. The limitations of a double hung window, is that the sashes will always be in the way of a total window opening. The screen on a double hung window, is located on the exterior of the window and is susceptible to the elements.


  • Single hung window. Not as common as the double hung window, the single hung window only has one sash that is operational. In most normal instances, the bottom sash is the operable sash and the upper sash is fixed. The fixed sash will not slide to open or close. The single hung window also has window tracks on the interior sides of the window frame, however, only one set of tracks is required due to the limitation of only one operable sash. Single hung windows are more common in commercial buildings, or if the budget needs to be reduced and economy is important. The screen on a single hung window, is located on the exterior of the window and is susceptible to the elements.


  • Sliding windows. Although both the double hung window as well as the single hung window have sliding window sashes, the term sliding window normally refers to a window that slides from side to side within the window frame horizontally. Both the double hung and single hung windows slide from the top to the bottom or vertically within the window frame. Sliding windows are available as single sliders or mulled ( connected ) together, to allow additional sliding panels. As with the double or single hung windows, the slider must slide across another panel, not allowing the full framed opening to be clear of obstructions. When ordering sliding windows, it is necessary to identify the sliding panel and the positioning of the sliding panel. An X is normally used to identify the sliding panel and an O is used to indicate the stationary panel. These designations are from the exterior of the structure, looking into the building’s interior. The screen on a sliding window, is located on the exterior of the window and is susceptible to the elements.


  • Casement windows. A casement window is a hinged window panel that is operated by a window cranking mechanism. A casement window can be a single casement window or a double casement window. The placement of the hinges and the locking mechanism must be designated when ordering the windows. A horizontal V is the normal designation on a casement window, with the apex of the V pointing towards the side of the window that the hinges are located. This designation is from the exterior of the structure looking into the interior spaces. The designation FCL identifies a casement window with the hinges on the left and FCR identifies the hinges on the right. One important positive aspect of a casement window is the ability to open the entire window area without any obstructions. An important negative aspect is that the window opens out, and there must be ample room, out from the facade of the structure to allow the casement to open and close uncompromised. A French casement window has no center support, the hinged sash from each side simply closes against each other, without another structural vertical mullion or support. Casement windows are normally installed in contemporary or commercial structures, or as special windows within a sun porch or common area. The screen of a casement window, is located on the interior of the window, therefore eliminating the deterioration due to weather that an exterior mounted screen will incur.


  • Hopper window. The hopper window is basically a casement window with the hinges at the bottom of the window frame and the window lock, on the top of the window. A hopper window swings out from the top and basically looks like a type of hopper when opened. Hopper windows are not very common, and are only used in special occasions or circumstances. The negative aspect of a hopper window is the vulnerability to damage, by anything falling or simply pushing down on the opened window. In addition, the hopper window is susceptible to water issues due to its upward opening. A hopper window allows the total opening of the window, and does not impose any obstacles within the frame of the window. As with casement windows, there must be adequate room on the exterior of the structure to allow the opening of the hopper window. The screen of a hopper window, is located on the interior of the window, therefore eliminating the deterioration due to weather that an exterior mounted screen will incur.
  • Awning window. The awning window is the opposite of the hopper window. The awning window is hinged on the top of the window frame, and the lock is on the bottom of the window frame. An awning window swings from the top and looks like an awning when opened and viewed from the exterior. The awning window will allow a full opening of the window and will not have the water concerns of a hopper window. As with the casement and hopper windows, there must be adequate room on the exterior to open the window. The screen of an awning window, is located on the interior of the window, therefore eliminating the deterioration due to weather that an exterior mounted screen will incur.


  • Bay window. The bay window is a name commonly used to identify a window that is constructed of a single larger glass panel in the center, with two or more flanker windows on either side. Dependent upon the design and the architectural requirements, these flanker windows could be double hung windows, casements, hoppers, awnings or any combination of these window types. The bay window is commonly used to introduce a large and wide expanse of window, and due to the configuration, allows the extension of the floor at this window. Perfectly suited to the dining area or a formal type living environment, the bay window allows creative architectural design possibilities. The bay window configuration is also an excellent choice, if a window seat or window storage area is required.


  • Bow window. Similar to the bay window, the bow window is normally a greater number of window units, mulled together ( attaching several window units together ), to form an arch or almost a semi circle of windows. Similar to a hunting bow, the form of a bow window allows creative architectural possibilities, and produces an interesting component to the facade of a structure. As with the bay window, the ability to gain additional interior floor space, or the use of this area for window seat, are all possibilities, if a bow window is installed. Bow windows are in many instances, constructed of casement type windows, however all different configurations of windows can be used to facilitate the construction of a bow window.


  • Eyebrow window. Very rarely used, the eyebrow window is a flat, semi circular window that emerges from the roof of a structure. Resembling an eyebrow, this type of window is normally a custom window that is extremely costly to construct and install. The use of an eyebrow window is an older feature for traditional homes, when the labor rates were considerably more reasonable than today’s labor rates. The construction of an authentic eyebrow window requires a craftsmen’s skill, and the art of the proper installation is fading as the popularity of the window fades. Normally the eyebrow window is not a functional window, but is a fixed window installed within the flattened semi circular frame.
  • Sunburst. This term refers to a window that is normally installed over the top of another window, and presents a sunburst effect ,by radiating the mutin bars or separators within the window itself, out from the center of the window base. This type of window is almost always constructed of a fixed panel of glass and are normally special custom orders. There are varying types of sunburst windows that are more oval than a perfect semi circle, or anything in between. A sunburst is basically a custom window, requiring a special order as well as a long delivery time.


  • Skylights . A skylight is a window that is mounted within the roof structure, and allows the sunlight to enter the interior of the structure. A skylight can be a fixed glass panel or an operable glass panel. Normally any operable skylight is hinged at the bottom or the top of a panel with limited opening depth. An insect screen can be installed on operable skylights, and the screen is on the interior of the window away from the exterior weather. Skylights, if reachable, can be operated manually, or if too high up in the ceiling, can be operated electrically. A skylight provides creative architectural features, increases the illumination of the room, as well as provides ventilation in the room. Skylights can accommodate the need for ventilation within a bathroom or provide privacy as needed in combination with allowing light to enter the room.
  • Stain glass windows. A stain glass window is commonly a custom window that is associated with the specific use of the structure. Very popular in churches and meeting areas, the stain glass can tell a story or convey a theme. Stained glass is extremely custom and is an artistic impression that has no limits. The only limit to a stained glass window is the cost. Stained glass is extremely expensive and if constructed in the original fashion, cut glass and lead joints, the beauty as well as the cost is unmatched.


  • Fixed glazing. A fixed glazed panel is a glass panel that is permanently installed within a window frame. There is no ability to move the glass nor is there any opportunity to open or close the glass panel. Fixed glazing is customarily used for storefronts and commercial installations. If used within the residential marketplace , it is designed as an architectural element for visual appearance, or for the ability to visually see through from one area of the structure to another. Fixed glazing is also the small vision panels that are commonly seen in doors and side-lites.


  • Storefronts. The term storefront is used to describe a combination of glass and doors that is most commonly used in commercial retail stores. The use of storefronts in residential construction is very rare, however, in some larger structures with architectural features a combination of full height glass and entry door is designed into the structure.


  • Replacement windows. The definition of a replacement window is a new window that is installed in the location that another window had existed. Replacement windows can be installed within the framework of the old window, or the old frame could be removed and a totally new unit, with a new frame can be installed. In some cases, a replacement window is only a replacement of the sash itself. The marketplace is rich in various selections of replacement windows and the research suggested for selecting new windows should also be done when selecting replacement windows.


Types of common doors;

1.) Single leaf door. This designation references a door that can be a swing or sliding door. The designation, single, identifies the number of actual door panels involved. A door leaf is a term that describes the swinging or sliding panel of the door. In most residences the majority of the doors are single leaf doors. Bedroom, bathroom, closet doors are normally single leaf.

2.) Double leaf door. This designation references a double door that can be a swing or sliding door. Like the single leaf door, the double, identifies the number of actual door panels involved. Used commonly for the entry door, doors into the dining room, exterior terrace doors, or any situation that will require a large opening for aesthetics or function.

3.) Swing door. This is the most common door, and refers to a door that swings to open or close. Swing doors are normally identified by the hand of the door. What this refers to is the swing of the door as noted from the exterior of the room. If the door swings into the room and the hinges are located on the right hand side, this is a right hand door. The opposite would reference a left hand door. This designation is important to understand to properly coordinate the swing and hardware placement on a particular door panel. A common method of identifying the swing of the door is to place your butt against the butts of the door. The butts are the hinges of the door and your butt is just that. Whatever arm swings to reflect the swing of the door is the hand of the door.

4.)   Sliding door. This is a door that either slides over another door panel or slides into a compartment constructed within the interior partition of a structure. The use of a sliding door in most situations saves the need to manage and coordinate the room required to accommodate a swinging door. If the sliding door, slides into a pocket in the partition, this is called a pocket door. Pocket doors are extremely handy when space is limited and there is no room for a swinging door.

5.)   Bi – fold door. This is a two or multiple leaf door, that is hinged between the door leafs. This hinging allows the full opening of the doors for closet access or other applications that required doors that open and close within a common frame. The best way to describe a bi-fold door is that they function in an accordion fashion.

6.) French door. This is a swinging door that is normally supplied in pairs. The center of the two swinging doors does not have a support or obstacle in the opening and allows the full opening of the entire door frame. French doors are commonly used to access porches, decks or used on the interior of the structure to separate different room applications, such as a division between the dining room and the living room.

7.) Double swing door . This is a type of door that swings in both directions. Commonly used for kitchen to dining room access in restaurants or residential kitchen to dining room interfaces. A double swing door allows the user to move in both directions without hitting a door stop.

8.) Fire door . A door that is designed to resist a fire for a specific amount of time. There are one hour rated fire doors, 90 minute doors as well as higher levels of ratings. A fire door is constructed of a non combustible material that will delay the advancement of a fire for the specified design time. Fire doors are commonly used between the garage and the home and the mechanical rooms within residential construction. Fire doors are very common in commercial construction, especially multi- family dwellings, medical facilities, schools or wherever there will be a large amount of people gathering together.

9.) Smoke door. A smoke door is a door that is sealed when closed to keep smoke and contaminated air from moving through the door opening. Smoke doors are specially designed and constructed to ensure that all perimeter separation between the door frame and the closed doors is sealed and tight. Smoke doors are used to stop the spread of smoke from a fire throughout the structure and are important elements to a properly designed structure that complies with the fire code regulations.

10.) Flood door. Similar to the operation of a smoke door, the flood door is designed and constructed to stop the flow of water through the opening. A flood door is normally a very heavy door that is custom built to accommodate the flood design criteria for the area and the BFE ( base flood elevation ). A flood door can be designed to act as an independent door, to be used only if a flood situation occurs, or a common door that is used during everyday movement within the structure. Flood doors are important elements in the efforts to provide flood mitigation criteria to shoreline structures.

11.) Bilco door. The bilco door is a common reference to a door hatch specifically designed and manufactured to accommodate access from the exterior of the structure to the basement elevation. Although Bilco is a specific company name, the use of this term, like using Jacuzzi as a term for whirlpool ,has become commonplace. A basement access hatch, a basement exterior grade level door or any other identification of a doorway that allows access from the exterior grade to the basement elevation is a basement door.

12.) Louvered door. The use of a door that has an air louver installed. The door can be a swing door or sliding door. A louver is installed to accommodate a ventilation requirement for areas such as closets, boiler rooms, mechanical rooms, etc.

13.) Acoustical door. This is a specialty door that is designed to eliminates, or reduce noise transfer. Commonly used in recording studios, special music rooms, practice rooms, etc. , an acoustical door will have weather stripping installed around the perimeter and special insulation within the core of the door, to reduce the noise transmission. Acoustic doors are rated with a STC rating, which is a sound transmission coefficient and can be manufactured at different STC ratings. The higher the STC rating the more sound is absorbed by the system and the less transfer of noise through the door.

14.) Darkroom door. This is a specialty door that blocks out all ambient light from being transferred around the perimeter of the door. This type of door will have the ability to perfectly seal the opening, eliminating any light penetration anywhere within the assembly of the door.

15.) Dutch door or split door. Both designations are used to describe a door that is split in the center of the door. Commonly used in kitchens, pantries, or quaint colonial designs that would accommodate the transfer of items over the open top portion of the door together with the ability to stop entry into the space. A split door can be used in a situation that would require the security of a closed door, together with the practicality of allowing movement of materials through the door. In some instances a shelf is installed on the bottom section of the door to allow the placement of items on the shelf for pickup.

16.) Terrace or patio door. This designation can be mixed up with such names as a French door, a sliding door, etc. However, in most cases, the terrace or patio door is an exterior door that is designed to allow access to an open patio or terrace. These are very common in residential homes as well as multi-family dwellings. Care must be taken to distinguish what the actual meaning of this term is due to the tendency of architects, residential builders, and interior designers to use the term in different ways.

What are some specific recommendations that should be considered when selecting a door or window for your home.

1.) Availability. The selection of a specialized manufacturer for your door and window selections may appear to be a perfect avenue to secure the perfect, custom doors and windows. This is correct insofar as customization and specific product requirements. However, the future availability of spare or replacement parts, or the requirement for addition window or door units for an addition or renovation must be considered. It is my opinion that although not totally custom, the selection of a prominent door and window supplier will ensure the ability to obtain the spare and replacement parts as well as match the doors and windows, if additional units are required.

2.) Maintenance and durability. The ability to maintain your doors and windows is directly affected by the durability of the product. If the durability is high, then the need to maintain is low. If the durability is low, then the maintenance is high. This is all common sense, however, the level of importance that these two characteristics is, in many instances, not as high as it should be. Most home owners as well as commercial structure owners do not want a continued maintenance issue, nor do they need the expenses of continually adjusting and maintaining the doors and windows of a structure. These characteristics are extremely important and should not be overlooked by the seduction of a special size or color or function.

3.) Ease of cleaning. No one wants or loves to wash their windows! I probably can make this statement almost universally. I have never had anyone indicate that they love to clean and wash windows. Therefore, with this in mind, the ability to easily and efficiently wash your windows should be a high priority in their selection. This also involves the selection of doors and door panels. Some manufacturers claim to have special insight into the ability to clean their windows and doors. I recommend that you go and actually try to slide or pivot or maneuver the sash of a window you are considering, as though you are in the process of cleaning the window.

4.) Grill layout and mutin assemblies. If the windows and doors are not true divided lights, which means the grilles are genuine and actually separate different panes of glass, then the type of grillage and mutins must be considered. If the grills are the common wood or vinyl, single piece grills that are meant to be removed from the window prior to cleaning, make sure they are constructed to allow the repeated removal of these items. I have discovered that the constant removal and re-installation of these elements of a window and door assembly will tend to loosen the connections and cause these grills to self destruct. If this is the case, their replacements should be off the shelf products that are easily available from the local builders supply or hardware store.

5.) Functionality. The function of the window and doors selected is once again, a common sense consideration. However in many instances this common sense value is overwhelmed by the special characteristics of what I call ” bells and whistles” It is important that the functionality of the product be the number one priority in the proper selection of the correct doors and windows for your home. How do the balances work within the frame of the window, are there small and delicate pieces of plastic, vinyl or metal that could break and require replacement as the doors and windows are repeatedly used and abused? The functionality of the products is inherently important to the overall satisfaction and this is probably the most important characteristic that should be considered.

6.) Material used. The materials used for your door and windows is important to the overall performance of these products. Wood is the commonly accepted, old solution to the overall question of the best material, however, I caution you when falling into this trap. Yes, the older windows and doors were all constructed of wood products, however the new synthetic materials had not reached their current level of design performance. Vinyl, aluminum and plastic have evolved into substantial materials for construction use. Their ability to withstand deterioration, moisture compromises, mold, rot and structural deterioration resulting in failure is far superior to some of the older, commonly used materials. In addition, the insulation factors and energy efficiency of the new products is far superior to the older type construction and assemblies. Please consider the research and development costs and advancements that manufacturers have included within their window and door packages.

7.) Hardware. The hardware used on doors and windows is constantly being updated and improved. In my opinion the most important aspect of proper hardware selection is to be able to have a good supplier of spare and replacement parts. There is nothing more frustrating than the inability to find a replacement handle for a casement crank or a cam lock for a double hung window. Make sure that the hardware is available locally to ensure replacement. When looking at windows and doors it is common sense to identify the pieces of hardware that are susceptible to breakage. These would be the small pins, the weak looking locks, small and inadequate handles, etc. No matter how the window is manufactured, if the hardware continues to fail, the entire system will become very frustrating.

8.) Ease of function. What I mean by this is the actual ease at which the door or window opens and closes. It is important that the friction in operation is minimum and that there is no possibility of a window or door becoming stuck in a closed or open position. When the window and doors are tested, make sure you feel the flow of the operation as smooth. Constant tugging and pushing on a door or window will result in the hardware becoming loose and the weather stripping compromised.

9.) Cost. The cost of the windows and doors is normally a direct indication of the quality of the product. However, as with all products, there will be the alleged cadillac of the marketplace, the window or door that everyone has, and everyone needs. With the constant advancement in the design and construction of doors and windows, manufacturers are solving a lot of the inherent problems that these elements of construction have always had. The reality that both the windows and doors are constantly moving and operating elements, will cause wear and tear issues, that manufacturers are attempting to solve. In regard to cost, I would recommend that t the products that fall in the middle of the cost band would be my starting point in your research and eventual selection. If you find that after researching the marketplace, you are not getting any additional meaningful improvements the more you spend, then you will have found your price range. Just because the product falls under the heading of ” must have ” does not necessarily identify the best product that will function and service your needs.

It is important to spend time in research and investigation regarding your doors and windows. Hopefully you will have these elements installed in your home for the entire time you own the home. Travel around, test the products and talk to individuals who have used the doors and windows you are considering. You cannot spend too much time in your door and window selection.


Summary of most common window and door terminology

Active Panel

The panel or sash, that operates by sliding or swinging, on a window or door unit.


The decorative piece of trim located under the window sill on the interior of the structure. This could reference a piece of architectural trim at the bottom of the window on the exterior also, but normally referenced to interior trim.

Argon gas

The gas used between panes of glass to further the insulating qualities of the sandwiched glass panels.


Refers to a trim piece that covers the interface of assembled window or door units. There can be an interior or an exterior astragal to cover the point of assembly.

Authentic Divided Lites (ADL ) same as True Divided Lites

Referencing the separation of glass panels within a door or window unit. If the glass panels are divided with an actual piece of wood, or synthetic material, creating actual separate panels of glass, then this separation is a authentic or true division of the glass panels.

Awning Window

A window unit that includes the hinging of a window sash at the top of the window frame allowing the opening to the exterior to resemble an awning when the window is opened.


Any mechanism assembled within the interior of the window frame sides ( jambs ) to facilitate and assist in the opening and closing of the window sashes. Original window balances consisted of heavy weights and actual rope, to assist the operation of the window sash. The term comes from the balancing effect of the weight of the jamb weights and the actual window sashes.

Bay Window

Normally the assembly on an angle of two, double hung window units, with a fixed panel window in the center of the two double hung window units. However, a bay window could consist of several window units assembled together, to accommodate a partial projection of the window unit from the exterior plane of the structure. The term is commonly intermixed with the term bow window, which will be the assembly of numerous separate windows, to form a crescent looking projection.

Bow Window

The assembly of several window units to form an almost crescent shape window projecting from the exterior plane of the façade of the structure. The bow window and the bay window are commonly intermixed. Normally, the bow window will have more separate window units in the total assembly, however the two terms are used interchangeably and the actual meaning and intentions should be clarified to avoid a common confusion.

Brick Molding Casing ( BMC )

This is commonly the trim piece that interfaces between the window, or door frame, and the exterior façade surfacing. Although the term brick molding infers that brick is the material installed on the face of the structure and therefore interfacing with the door and window trim, this is not always the case. The term is widely used to reference the interface between any type of exterior façade material, and the window or door frame itself.

Bullet proof glass

Glass manufactured to deflect or absorb the impact of a bullet. This glass is designed as a laminated assembly of several layers of glass as well as strengthening sheathing made of a synthetic material. Each manufacture will have their own special process to produce bullet proof glass and each product will withstand various force projectiles.


Another term for door or window hinges.

Cam lock and pivot mechanism

The term used to describe the locking mechanism on double and single hung windows. Sash locks and window locks are terms that are also used in many cases to indicate the same mechanism.

Casement Window

A window that is hinged on one side of the frame, and latched on the other side of the window frame.   A casement window, normally swings to the exterior of the structure, allowing the installation of an insect screen on the interior of the window unit. The benefit of a casement window is the ability to open the entire window area for maximum ventilation. The negative aspect of a casement type window is the room required on the exterior, to allow the casement to fully open. Casements are more popular in a contemporary home or office environment.


Any material that is applied to the surface of another material, to provide durability, architectural design, solar gain or protection, or any other decorative or functional reason. Aluminum and vinyl cladding are very common materials that are used in window manufacturing, to protect the sub-base material which is normally a wood product. Cladding is a very common term and can be used to describe almost any material, applied as a covering over another material.

Combination / Storm, door, window

The term, combination, is used by various window and door manufacturers, to reference the combination of storm and screen panels stored within their window and door assemblies. In many instances, the panels are stored in a compartment that is part of the entire assembly, and are available to use as needed. This feature is a very important aspect of the merchandising of various windows and doors. It is a very popular feature for the homeowner, who does not have separate areas to store either storm windows or screens.

Cottage Window

Term that references a window that has different size sashes. Normally the upper sash will be smaller than the lower sash. In many designs, the use of a cottage window is located on the front façade of a home to provide a county effect. Cottage window is a term used with double or single hung windows.

Daylight opening ( DLO )

The actual glass size that is visible. Easily remembered as the area of glass allowing daylight into the structure. NOT the entire size of the glass panel due to the additional glass required to allow proper positioning and installation within the sash that is not visible and covered by a window stop.

Depth of jamb / Jamb depth

The depth of the framed opening required, in reference to depth of the exterior wall framing. This will depend on the total framing of the structure, inclusive of sheathing, framing, insulation, etc. If common 2 X 4 framing is used, a standard jamb depth is identified, if heavier framing is used, then a jamb extender or jamb trim piece, maybe required to accommodate the depth of the entire system. Current insulation requirements are causing the jamb depth to increase as additional insulation is added to structures.

Direct glazed or fixed glass

The application of a glass panel to the frame of the window without any sash assembly. This direct glazed unit or fixed glass is not movable and is stationary within the frame of the window. Normally found residentially as the center fixed glass in a picture window or in a door side lite. Commercially the fixed pane of glass is common between offices, in conference rooms, etc.

Divided lites

The separation of glass by what is referenced as mutin bars. These bars can be artificial and installed within the space between the insulated glass, which is called simulated divided lite, or they can actually be separated by real pieces of wood or synthetic material, forming a true divided lite. To simulate a divided lite assembly, the use of removable grills is a popular method. This presents the appearance of a divided lite, without the cost, and the ability to clean the glass is easily accommodated by removing the grill from the actual window sash. Colonial design normally consisted of true divided lite panels due to the inability to manufacture larger pieces of glass, in one consistent and clear unit.

Door assembly

The joining, in a common assembly, of different door panels and types, to form a single entity for ease in installation or stability purposes.

Double Hung

Double hung windows are windows that have two separate window sashes. Each window sash is operational and will slide vertically, up or down. The double hung window can be provided with equal window sashes or with unequal sashes, reference the cottage window. Double hung windows are extremely common in residential structures or multi- family buildings. The use of double hung windows in commercial structures is typically uncommon.

Drip cap

Any piece of trim or molding that is installed over the top of a window or door, to ensure that any water shedding down on the top of either unit is projected forward, and away from the façade of the structure. The drip cap will ensure that the water is shed to the exterior of the structure, over the top of the window or door. Proper drip caps are important to the watertight integrity of the window or door. A properly installed drip cap will ensure that no water will penetrate in back of the window or door head, into the interior of the structure.

Electric operator

Any type of electric motor operator, which furnishes power to window openers, door openers, shades, skylights, or any other operating mechanism, to substitute the need for any manual operation of the opening and closing mechanism. Normally the electric operation of a window, door or other construction element will be required if reach is a factor or special operation of shades, skylights, etc is required for security reasons or privacy issues.


Any plate that covers an opening in a wall, door, window or other surface that has another component penetrating the surface. The plate covers the opening between the penetration and the finish surface, and in most cases, in a decorative fashion. Escutcheon plates are normally split in two halves to allow installation over the penetration after the installation of the piping, conduit, or other penetration has been completed.


The process by which, a metal, vinyl, or other synthetic product, is forced through a die that has a specific shape, resulting in a formed product. The process of extrusion is used to manufacture various trim pieces of aluminum or vinyl, customize the installation of asphalt or concrete curbing, or even used for structural steel elements. Extrusion produces a monolithic form, which is strong and consistent. Many of the trim pieces as well as the structural pieces of window and door assemblies are extruded.


Designation of a casement window that has the hinges on the left side of the window as viewed from the exterior looking into the structure.


Designation of a casement window that has the hinges on the right side of the window as viewed from the exterior looking into the structure.

Finger jointed

A technique that is used to attach the ends of a wood product, by cutting a tapered slot in the end of one piece of material and a similarly tapered finger in the end of the other piece. Normally there are several repeating slots and fingers cut, to allow a consistent and strong bond between the two pieces of wood. The wood is normally glued together and forms consistent and strong pieces of product, that are more resistant to warping and moving, than a similar full length of wood.

Fixed lite

More common in commercial construction than in residential, the term fixed lite is used. This references the use of glass in framed openings without any ability to operate the pane of glass. Used as vision panels in doors or offices, the term fixed lite is a common description of scattered lite panels designed throughout a structure’s interior to allow visual access from one space to another.

Flat casing

Any product that is used as a trim piece, which is flat on all sides and has 90 decree corners. A piece of flat stock or casing is a simple piece of wood, aluminum or steel without any type of miters, special routed surfaces, etc.

Foot bolt

Mechanism at the bottom of a door panel, that allows the activation of a pin assembly, that engages in the sill of the door assembly, providing a means of securing a door panel from moving. Used in double swing doors to secure the inactive door or sliding panels to secure one panel from sliding. Stability of the fixed panel is maintained by the use of a foot bolt as well as a head bolt.


Door or window frame consists of the assembly of wood, vinyl, metal or other synthetic product around the opening of the assembly. The frame is secured to the perimeter framing of the opening and consists of the head (top) two jambs (sides) and the sill (bottom) of the opening. In most installations the installation of the door or window frame is secured with the use of screws and tapered shims to allow adjustment of the door or window frame in the rough opening. The proper installation of the door or window frame within the rough opening is essential to the proper functioning of the door or window. Out of level or racked frames for doors or windows will result in difficulty opening and closing the door or window.

French or open casement

Double window unit, that swings out with hinges on the sides of the frame, to present an unobstructed full window opening. No middle astragal or framing piece is used, identifying the double casement as a French unit.

French door

Similar to the French casement, but sized as a door unit. A French door can be designed and manufactured to swing either in or out of the structure.


A process that is applied to the glass to produce a frosted appearance on the glass. The process can be done in the factory at the time of manufacture of the glass or it can be done remotely on the jobsite. Frosted glass is a good accommodation, if the visual clarity of the glass is not required for either privacy or security purposes. There are special subcontractors that specialize in the frosting of infield glass.

Glass block

A unit, similar to a masonry unit, but constructed in glass. Glass block is used as an architectural feature that allows a diffused light into the interior of the structure without visual clarity. Used for privacy features as well as interior design accommodations.

Glass size ( GS )

The actual size of the glass, and not only the visible glass. Any insertion of the glass into mounting grooves or stops, installed on the sash, must be included when specifying the GS or glass size. These dimensions of glass, would be the dimensions that are required to properly order a replacement piece of glass.


The act of installing glass in windows, doors or fixed openings. To glaze a unit would be the actual installation of a piece of glass within a frame or sash.

Glazing bead

Trim pieces of wood, vinyl or aluminum that are installed around the perimeter of the sash, to secure the glass in the sash. Glazing bead is installed with small nails, staples, or specially designed clips. The glazing bead is designed to fit into the sash and create an architecturally pleasing appearance.

Glazing tape

Double sided adhesive tape, which is installed on the rabbeted perimeter of a sash. The double sided tape adheres to the glass as well as the sash frame, normally on all four sides.


Similar to the slider, a window or door panel that slides along an upper and lower track assembly. Normally the glider assembly involves one sliding unit and one stationary unit.


Removable wood, vinyl or aluminum dividers, that are installed over the entire glass panel of a window or door. The grilles are easily removable to allow cleaning and to simulate true divided lite assembly on the window or door unit. Grilles are common in residential construction, especially in more traditional architectural designs. In some instances, grilles are designed and installed within fixed interior glazing for architectural effect.


Descriptive term used to identify the location of the hinges, strike, and swing or slide direction of a door or window. Handing is important to understand when ordering frames, doors and windows, and will clearly identify to the distributor, all of the necessary information required to properly order a window or door, which functions in accordance with the intended purpose and design. The best method of identifying the basic handing of a swinging door is to place your back against the hinge side of the door, and dependent upon which arm represents the swing of the door, will indicate the swing of the door. If your right hand resembles the door swing, then this is a right handed door and frame, if the left represents the door, it is a left handed door and frame. More sophisticated identification that indicates the location of the hardware, the side of the door that is lockable is referenced as left hand reverse, right hand reverse, etc. It is best, when ordering doors and windows, that a professional consultant or distributor be used to ensure that the doors and windows are coordinated and properly ordered.


Top of a window or door. The jamb is the sides of the opening and the sill is the bottom. The term head, is in many instances used to describe the top of any construction element and not necessarily just windows and doors.


Same function as the foot bolt, except the positioning is on the top of the door or window. This mechanism eliminates the movement of the door or glass panel. In many instances, used in conjunction with the foot bolt for security and stabilization purposes.

Hurricane proof glass

As with bullet proof glass, this is a special design and manufacture of glass to withstand hurricane force winds and rain. In many instances hurricane proof glass is also designated as Miami Dade glass named after the area of the country that has required this type of glass for several years. This type glass is an assembly of several layers of glass, fused together with special layering of sheathing to accommodate the pressures and impact which occurs with hurricane force winds and rain. In addition, the design of an entire hurricane proof window system involves the design and construction of heavy framing members and support pieces. Hurricane proof glass is much more expensive than normal glass and requires special manufacturing of the products.

Inactive panel or sash

Any door or window panel, that is not the primary sliding or swinging panel. Inactive identifies an assembly that remains stationary during the normal function of the door or window unit. In many instances the inactive panel or sash can be made active if locking mechanisms are disengaged.

Insulated Glass

Double or triple panes of glass assembled as a unit, with a gas installed between the panes of glass to provide additional insulation and to eliminate condensation build up within the glass panes. Insulated glass is common for the glazing of windows and doors, due to the increasing demand for energy conservation and improved insulation values.


Window or door unit that swings inward, towards the interior of the structure.

Interior casing

Interior trim around the window or door opening, installed to cover the interface of the window or door framing and the interior wall surface. Normally consisting of a wood material and installed by a finish carpenter. The interior casing could include jamb, head, window sill, apron, etc.

Jamb extensions

Pieces of wood or vinyl, sized to accommodate varying exterior wall thicknesses. An increase in exterior wall thickness has become customary, due to the additional insulation required for the exterior walls of a residential home or commercial structure to adequately comply with the new insulation requirements.

Jamb liner

Smaller pieces of wood or vinyl, in comparison to the typical, full size, jamb extensions. These jamb liners provide custom size depth of window and door frames, to accommodate varying thicknesses of exterior wall construction. The need for jamb extensions as well as jamb liners has become increasing more common, due to the amount of insulation being required and installed within exterior walls.


The occurrence of a misalignment, that causes a functioning element in a door or window, to stop working due to excessive friction, or the inability to slide, swing, tilt or function.

Keyed cylinder lock

Cylinder lock that is operated by a key as opposed to a simple thumb turn or lever to activate the lock.

Krypton Gas

Inert gas used to fill voids between panels of glass within an insulated glass assembly. The gas is used to increase the insulation factor and decrease the probability of condensation forming between the two or more panels of glass. Various manufacturers will use other types of gas depending upon the function of the glass.

Laminated Glass

Two panes of glass, fused together, with a sheet of clear plastic in the middle of the two panes of glass. This will allow the breakage of the glass without separation and failure. Laminated glass is commonly used as a safety glass due to its ability to remain in one piece when broken. In some cases the use of tempered glass in lieu of laminated glass is utilized.


Locking mechanism used on doors or windows. A lockset will include the locking mechanism, as well as the keys to operate the lock. This reference is opposite to a simple latch or passage set, which is a simple mechanism that includes a strike and bolt, that can be operated by a knob or lever, without the means of locking the mechanism. Locksets are normally used for privacy or security purposes.

Low E Glass

Low E is a descriptive term, referencing the reduction of the emissivity of the glass. The lower the emissivity of the glass, the less radiation is allowed to pass through the glass, thereby improving the overall thermal performance of the glass. Normally low E glass is manufactured by installing a light layer of metallic oxide on the surface of the glass. This layer is virtually invisible to the eye and also reduces the overall heat gain of the glass. Low E glass has become a design standard with various manufacturers producing different grades of low E glass and devoting substantial research and design money to improve the glass performance regarding reduction of emissivity.

Masonry opening ( MO )

The rough opening required in a masonry wall, which will allow the proper installation of a window or door unit. The masonry opening will be calculated to allow the necessary additional room for the adjustment and correct installation of the window or the door. Normally a shim space is allowed, both vertically and horizontally, to allow the installation of tapered shims to correctly position the window or door unit.

Miami Dade

This is normally a reference to the building code requirements of an area in Florida, identified as the Miami Dade county area of the state.   These requirements are the most stringent in the United States and are meant to withstand hurricane force winds and rain that accompany hurricanes within the Miami Dade region. Many manufacturers of glass and glazing assemblies cannot provide products that comply to the Miami Dade design standards. There are only a specific number of manufacturers that can provide the wind and rain resistance required by these codes.

Mortise and tenon

A form of joinery that is used on window and door assemblies to improve strength and longevity. The joint is made by cutting an opening in the receiving member, called a mortise, and then cutting a tenon in the adjoining piece, to allow insertion of the tenon into the mortise. Normally glue is used to secure the pieces together.


Descriptive term for attaching two or more window or door units together to form a single assembly. To mull windows or doors, is to attach one to the other. The common side of two adjacent windows or doors is normally called the mullion and a mullion cover is used to cover the adjacent members.


Many times used interchangeable with grilles. A muntin is a piece, horizontal or vertical, in a window or door unit that extends from a rail or stile or from one mutin to the other. Muntins are grilles, and in most situations, the same designation can be used interchangeably.

Nailing fin, leg or flange

Manufacturers of vinyl or aluminum windows and doors will normally install a nailing fin, leg or flange to allow the installation of a window unit. The nailing fin is positioned tight against the exterior sheathing of the structure, normally on all four sides, and is nailed or screwed into the exterior façade of the structure, to position and stabilize the window or door unit. This nailing fin, leg or flange is attached to the window or door unit at the factory or shipped loose and installed in the field, dependent upon the manufacturer and the design.

Non – keyed cylinder

A cylinder lock, which does not have an exterior key opening. This type of lock can only be locked from the interior of the structure. Normally the locking of this type of non-keyed cylinder is operated with a turn knob or lever and not a key.

Obscure Glass

Glass manufactured to obscure the visual ability to clearly see through the glass. This glass is used in areas requiring privacy or security. The term obscure glass can reference tinted glass, smoked glass and frosted glass. Any glass that clear visibility is not a characteristic of the glass.


Term used to describe the operation of a door or window panel. Normally the designation of an X is used to indicate the operational unit and the designation O is used to mean the non-operational unit. When describing a window or door assembly these designations are described as you look at the window or door from the exterior of the structure.


Outside measurement This is the exterior measurement of the entire window or door unit.


Window or door unit that swings outward, towards the exterior of the structure.


A term used to describe an extruded aluminum or vinyl covering over a window or door jamb, head, or other component. Panning is a universal construction term and can be used to describe any type of covering.

Passage set

A hardware set that allows the functioning of a bolt into a door strike without the ability to lock the mechanism. Normally used in areas that do not require security or privacy. Used as a means to hold the door shut without any ability to limit movement in or out of the space.

Picture window

Used to describe an assembly of windows, consisting of a larger fixed glass window in the center, flanked by casement or double hung windows. In some instances the term is used to merely identify a large section of fixed glass without any flanking windows. The term originated due to the overall effect of the visual look of the window from the interior of the structure. Normally the casing is a continuous window frame with no sill or apron.

Privacy set

A hardware set that allows privacy on one side of the opening. Commonly used in bathrooms to allow privacy from the bathroom side with common entry from the exterior of the bathroom. In most instances the activation of the lock, is a simple push button, which locks the hardware set and not a key. The common side of the privacy set has an access hole in the center of the knob or lever to allow the emergency opening of the privacy set if required. A simple insertion of a pin into the hole will force the mechanism locking the door to disengage and allow access into the space from the exterior.

Plynth block

A decorative trim piece that is usually located at the intersection of the window or door head and jamb assemblies. Interior designer will detail this trim piece to accommodate the interior design presentation of the structure. A very common colonial design is a pineapple design embossed on the plynth block.

Pole crank

A wood, vinyl or aluminum pole, that is specifically designed to allow operation of a crank mechanism for a window that is out of comfortable reach. The same type of application can be used for large double hung windows to operate the upper sash.



R – value

The resistance of a material to heat and cold. A means of identifying the ability of a material to insulate. The higher the R value the greater is the insulating ability of the material.


Term used to describe a cut out along the side of a piece of wood, vinyl or aluminum. A rabbet allows the flush installation of a flat piece of stock into the rabbeted piece of wood, vinyl or aluminum.


Term that is used to describe a misalignment of a door or window frame within the rough opening. Racked can mean a window or door out of plumb or basically crooked within the opening. This will prevent the proper functioning of the door and window and could cause glass breakage or jamming of the sash within the frame.


The length of a straight line, starting from the center of a circle and ending at the perimeter of the circle. The radius is used to describe the size of a circle or semi-circle such as a round top over a window or door.


The horizontal piece of a sash assembly, raised panel wood, or other assembly.

Rough opening ( RO )

The rough opening, is the full untrimmed opening for a window or door. The rough opening, like the masonry opening, will be calculated to allow the proper installation of the door or window, with shim space allocation to allow adjustment. Normal shim space can be as small as 1/4 inch, to as large as 1 inch on either side of the opening.


The section of the window that fits into the frame and holds the glass assembly.

Sash limiter

A mechanism that is installed to prevent a casement from opening beyond a specifically designed angle or a slider from opening further than designed. With double or single hung windows, a sash limiter can be installed on the jamb sides of the frame to limit the ability to open the window beyond a designed dimension.

Sash lock

Locking mechanism designed to lock the sash of a window



Sash opening ( SO )

The clear opening in the frame that the sashes will be installed into. Normally the sash opening does not include the tracks mounted on the jamb sides of the opening but extends directly to the frame surface itself.


Aluminum, fiberglass or metal mesh that is framed with wood, aluminum or vinyl ,to be installed into a window or door unit to eliminate insects and debris from entering the structure.

Side Jamb

The sides of a window or door unit.


Stationary glass units that are installed alongside a door or window unit. The sidelite, in most cases is non operable


The bottom of a door or window. This piece of frame will rest on the bottom of the masonry or rough opening.

Sill horn

The extension of the bottom of a window sill to the exterior of the window casing. This is a decorative choice and selection.

Single Glass

Single pane of glass as opposed to an insulated glass, which is two or three layers of glass, sealed together with an air space that is filled with a special gas, to increase the insulation performance of the glass. The use of single glass panels is becoming less common due to the need for increased insulation values as well as special requirements such as security, light transmission, etc.

Single hung

Same as the double hung window except the upper sash is non operational and stationary.


A piece of vinyl, wood or aluminum that provides the spacing between two pieces of glass in an insulated glass unit

Special low E glass

All glass manufacturers have various techniques to enhance their glass panels in regard to the low E ratings of the glass. Research and development has resulted in a significant reduction of solar heat coefficients, as well as providing additional protection from ultra violet light transmissions. Glass is constantly being improved and researchers are making new improvements all the time.


The vertical pieces of an assembly as opposed to the rails which are the horizontal members.


A trim piece of wood, vinyl, or aluminum that is installed in a door or window opening to limit the swing of a door or window. Normally a small narrow piece of wood, vinyl or aluminum.


A piece of trim on a window unit that extends the sill of the window and projects out into the interior of the structure beyond the plane of the interior trim. Normally an apron would be installed under the stool.

Storm sash

A separate fixed glass unit that is installed during the winter months and removed in the summer. In most cases, the storm sash is replaced with a screen in the summer.


Descriptive term for a semi circular window with mutins emanating from the center of the sill member evenly to the perimeter of the semi circular window


Used to describe a decorative or architectural trim around a window or opening. The surround of any unit normally refers to all the trim pieces that make up the perimeter of that unit.

Tempered Glass

A process that is used on glass that rapidly heats the glass, then rapidly cools the glass. This process makes the glass extremely strong and will break in small pieces that will simply shatter and drop away eliminating the hazards of large sharp pieces of glass.


The temporary replication of a glass size, or any other type of construction item, such as a countertop sink, that is used to order replacement glass or to position fasteners in the correct location. Templates are normally made to accurately describe a piece of complicated replacement glass.

Tilt windows

The term tilt, is a reference to the ability to actually tilt the window sashes out of the window frame to facilitate the cleaning of the individual window sashes. The tilt mechanism allows the window to pivot on pins that are located within the frame of the window and extend into the sash. The sash is secured in the window tracks with a pressure sensitive rail that can be compressed, to allow the sash to pivot into the interior of the home. This pivoting or tilting allows access to both sides of the glass, for ease in cleaning.


Tinted glass

Glass that has been treated to produce a tint to the glass, reducing the emission of heat from the sun. Treatment of glass, by tinting, in areas of the country exposed to severe sunlight, is very common. Like frosting, the application can be performed at the factory or in the field. Tinting produces a dark appearance to the glass and can be applied in varying levels of darkness.


The act of producing tinted glass.


The smaller window above a door or window. A transom can be stationary or operational. Large transoms are sometimes designed to accommodate ventilation requirements or to produce the illusion of door height, without the need to produce doors of exceptional size. The use of a transom above an interior door is a common method of filling the wall space architecturally, when high interior ceilings are encountered.

U factor

The measurement of heat transmission through a door or window from the interior to the exterior. The lower the U value the more insulating properties in the element being measured. This is opposite the R value or rating of an assembly ,which is the insulating properties of material systems. In regard to the R value, the higher the value, the greater the insulating properties.

Weather stripping

Any material or mechanism that is installed on the frame of a door or window to reduce the amount of air penetration between either the door unit or the window sash. Weather stripping is available for all different types of doors, windows and openings in the exterior wall. The proper application of weather stripping can substantially reduce the transmission of heat and cold thru the door or window. Remedial installation of weather stripping is a common energy saving process that is performed on existing doors and windows.

Window assembly

The joining, in a common assembly, of several window units, to form a single entity, for ease during installation or stability.

Window frame

The window frame, is the portion of the window that will guide and direct the window sash to move. The frame will consist of multiple tracks to guide a number of window sashes, dependent on the type of window selected, or will have other elements such as hinges, window cranks, window locks, etc.

Wire glass

A glass unit that has a narrow gage wire mesh installed within two glass panels. Wire glass is used as a safety glass and will not fall out of the frame when broken.


The designation showing the operable sash and the non-operable sash, slider or door. The X designates the operable unit and the O the non operable. This designation is determined from the exterior of the structure.

















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